Diachronic works in RDAPCC Operations Committee meeting
Library of Congress, 2 May 2019
What is a diachronic work?
A diachronic work is a work that is planned to be embodied over time, rather than as a single “act of publication”.
The essence of a diachronic work is a plan for the change of content.
Change of content = extension of content
How is content extended?
By accumulation (the addition of content in discrete physical or logical units): successive works
By replacement (new content is integrated with—and may replace—existing content): integrating works
In RDA these methods are specified by the extension plan element of the work entity
What is the extension plan element?
The extension plan element is a categorization combining values from two extension attributes of the RDA/ONIX Framework for Resource Categorization: Extension mode (succession or integration) Extension termination (whether or not period of extension has a
predetermined end: determinate or indeterminate) There is an additional category for resources with a static (non-
diachronic) plan
How are the values of the extension plan element recorded?
There is an RDA vocabulary encoding scheme (VES) for extension plan, with five possible values: Integrating determinate plan Integrating indeterminate plan Static plan Successive determinate plan Successive indeterminate plan
Integrating determinate plan
ROF extension mode INTEGRATION
ROF extension terminationDETERMINATE
RDA extension plan INTEGRATING DETERMINATE
Integrating indeterminate plan
ROF extension mode INTEGRATION
ROF extension termination INDETERMINATE
RDA extension plan INTEGRATING
INDETERMINATE
Static plan
ROF extension modeN/A
ROF extension terminationN/A
RDA extension planSTATIC
Successive determinate plan
ROF extension modeSUCCESSION
ROF extension terminationDETERMINATE
RDA extension planSUCCESSIVE DETERMINATE
Successive indeterminate plan
ROF extension modeSUCCESSION
ROF extension termination INDETERMINATE
RDA extension planSUCCESSIVE
INDETERMINATE
Serial work
How does this relate to IFLA LRM?
IFLA LRM (5.8 Modelling of serials) regards any serial as “a distinct instance of the work entity” [i.e. serials have a WEM lock] and uses specific relationships among these instances to connect them
The modeling of diachronic works in RDA is extrapolated from this modeling of serials in IFLA LRM
So does a work with a diachronicextension plan have a WEM lock?
Yes, any work with a diachronic extension plan may be realized in one and only one expression and embodied in one and only one manifestation, a 1:1 cardinality in each case
Any work with a static extension plan adheres to the standard WEMI cardinality: it may be realized in one or more expressions and embodied in one or more manifestations, a 1:Mcardinality in each case
Come again?
RDA explains this in terms of transformation boundaries A transformation boundary is a stage at which a work is treated as a
new work separate from the existing work For static works, a difference in content between two expressions is a
necessary but insufficient indicator that each expression realizes a different work (no transformation boundary has necessarily been crossed)
For diachronic works, the potential for a difference in content (inherent in the fact that content is embodied over time) between two manifestations is sufficient in itself to indicate that each manifestation embodies a different expression and those expressions realize different works (the transformation boundary has been crossed)
Work is a transformation of Work [LRM-R22]
Transformation by audience Carrier version
Language version
Regional version
Transformation by genre
Transformation by policy Transformation by extension plan
Transformation by style
So how does this affect continuing resources?
Not much For CR, RDA is simply implementing the
IFLA LRM modeling of serials Aligns more closely with ISSN practice Pretty much reflects current CONSER
practicePreferred title of translations and
languages editions = title proper
What about multipart monographs issued over time?
RDA treats any multipart monograph issued over time as a diachronic work with a successive determinate extension plan
RDA no longer treats “multipart monograph” as a mode of issuanceExtension plan: successive determinate planMode of issuance: multiple unit
Can you give an example?
Encyclopædia Britannica (3rd edition)
Initially published from 1788 to 1797 in ca. 300 fascicles
Volume title pages issued later, all with “1797” as date of publication
Now it’s getting personal…
w1 (static work): My dissertation e1 Typescript (with diskettes in pocket) e2 Typescript (without diskettes or pocket)
m1 Microfilm
m2+ Publish-on-demand from microfilm (several size and binding options)
m3 Digitized microfilm (ProQuest online products)
w2 (diachronic work): My dissertation, slightly abridged and published under what I thought was a catchier title in the vain hope of attracting a wider audience (or indeed any audience at all) W2.1-2.2 Contributions to 2 successive issues of Cataloging & Classification
Quarterly
How do I now bring together works that RDA might formerly have considered expressions of a single work?
RDA permits closely related works to be treated as work groups
Descriptions of these works might be brought together by recording an appellation of work group (assigned from a vocabulary encoding scheme) as part of the description of each work
For example, The Economist
Authorized access point for work group: Economist (London, England : 1843) Drawn from LCNAF vocabulary encoding
scheme (VES) LCCN: no2019022928
http://id.loc.gov/authorities/names/no2019022928
Identifier for work group: 0013-0613 Drawn from ISSN-L vocabulary encoding
scheme (VES) IRI:
https://www.wikidata.org/wiki/Q180089
For example, Encyclopædia Britannica
Authorized access point for work group: Encyclopaedia Britannica Drawn from LCNAF vocabulary
encoding scheme (VES) LCCN: nr89013909
http://id.loc.gov/authorities/names/nr89013909
IRI: https://www.wikidata.org/wiki/Q455
The future: relationships?
Historically, we used uniform titles to bring together expressions and manifestations of works in the context of an alphabetical catalog. This has created a sizeable store of legacy data predicated on this mechanism for collocation
Prospectively, appellations of work groups may serve this purpose (though the underlying semantics may be a bit messy)
In a linked data environment, however, relationship matrices may increasingly serve this purpose: Work A transformation by extension plan of Work B
The present: pragmatic question (MARC / BIBFRAME)
How will one identify an RDA authorized access point for work group (identifying the members of a work group) in MARC or BIBFRAME?
Part of the larger question of mapping from RDA to MARC and/or BIBFRAME and vice versa
Currently we map in our heads, which is not really a satisfactory Linked Data solution
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